Fuser and image forming apparatus

Abstract

A fuser includes a pressure application part that applies pressure to a medium for forming a print image; an annular body rotatably supported for carrying the medium for applying heat to the medium for forming the print image; a fuser part heat generation body arranged for generating heat to apply heat to the annular body; a first temperature detection end arranged in contact with one end part outside a medium carrying corresponding range of a surface of the annular body and detects temperature of the annular body outside the medium carrying corresponding range. The medium carrying corresponding range is a range in which the medium is carried. A heat generation interruption part that, in response to the temperature of the annular body that is detected via the first temperature detection end, interrupts heat generation of the fuser part heat generation body.

What is claimed is: 
     
       1. A fuser comprising:
 a pressure application part that applies pressure to a medium for forming a print image; 
 an annular body that is rotatably supported for carrying the medium in a manner that the medium is sandwiched between the annular body and the pressure application part for applying heat to the medium for forming the print image; 
 a fuser part heat generation body that is arranged on an inner side of the annular body for generating heat to apply heat to the annular body; 
 a first temperature detection end that is arranged in contact with one end part outside a medium carrying corresponding range of a surface of the annular body and detects temperature of the annular body outside the medium carrying corresponding range, the medium carrying corresponding range being a range in which the medium is carried; 
 a heat generation interruption part that, in response to the temperature of the annular body that is detected via the first temperature detection end, interrupts heat generation of the fuser part heat generation body; and 
 a reflection part that is arranged on an inner side of the annular body, and reflects radiant heat of the fuser part heat generation body toward at least the medium carrying corresponding range of the annular body and the one end part. 
 
     
     
       2. The fuser according to  claim 1 , wherein
 the fuser part heat generation body is arranged directly to apply the heat to the medium carrying corresponding range and the one end part of the annular body. 
 
     
     
       3. The fuser according to  claim 1 , wherein
 the heat generation interruption part is arranged in a manner that the first temperature detection end is in contact with the one end part that is an outer surface of the annular body. 
 
     
     
       4. The fuser according to  claim 1 , wherein
 in the heat generation interruption part, a predetermined resin layer is formed on a surface of the first temperature detection end. 
 
     
     
       5. The fuser according to  claim 1 , further comprising;
 a drive roller that drives the annular body to rotate; and 
 a fuser contact member that is arranged at a predetermined distance from the drive roller, wherein 
 the annular body is an annular belt, 
 the drive roller and the fuser contact member are arranged on an inner side of the belt, and further the belt rotates in accordance with rotation of the drive roller, 
 the drive roller and the fuser contact member both oppose the pressure application part and the belt is sandwiched therebetween, and thereby a predetermined pressure is applied to the belt and the carried medium, and here a sandwiching part is formed between a first sandwiching point (pt 1 ) where the drive roller and the pressure application part press against each other and a second sandwiching point (pt 2 ) where the fuser contact member and the pressure application part press against each other, and 
 the heat generation interruption part is arranged in a manner that the first temperature detection end is pressed against a portion opposing the sandwiching part on an outer surface of the belt. 
 
     
     
       6. The fuser according to  claim 5 , wherein
 the fuser contact member is a fuser part driven roller, 
 the fuser part driven roller rotates in response to the rotation of the drive roller, and 
 the second sandwiching point (pt 2 ) is formed between the fuser part driven roller and the pressure application part. 
 
     
     
       7. The fuser according to  claim 6 , wherein
 the fuser contact member is a driven roller that rotates in conjunction with the rotation of the drive roller, and 
 the first temperature detection end is positioned on the first flexible portion, which is between a vertical tangential line (α) at a most downstream position in a medium carrying direction on an outer periphery of the drive roller and a vertical tangential line (β) at a most upstream position in the medium carrying direction on an outer side of the fuser part driven roller. 
 
     
     
       8. The fuser according to  claim 1 , further comprising;
 a drive roller that drives the annular body to rotate; and 
 a fuser contact member that is arranged at a predetermined distance from the drive roller, wherein 
 the annular body is an annular belt, 
 the drive roller and the fuser contact member are arranged on an inner side of the belt, and further the belt rotates in accordance with rotation of the drive roller, 
 the drive roller and the fuser contact member both oppose the pressure application part and the belt is sandwiched therebetween, and thereby a predetermined pressure is applied to the belt and the carried medium, and here a sandwiching part is formed between a first sandwiching point (pt 1 ) where the drive roller and the pressure application part press against each other and a second sandwiching point (pt 2 ) where the fuser contact member and the pressure application part press against each other, and 
 the heat generation interruption part is arranged in a manner that the first temperature detection end is pressed against a first flexible portion (1utp) that is a portion other than the sandwiching part on an outer surface of the belt. 
 
     
     
       9. The fuser according to  claim 8 , wherein
 the fuser contact member is a fuser part driven roller, the fuser part driven roller rotates in response to the rotation of the drive roller, and 
 the second sandwiching point (pt 2 ) is formed between the fuser part driven roller and the pressure application part. 
 
     
     
       10. The fuser according to  claim 1 , further comprising:
 a temperature sensor that is arranged in a manner that a first temperature detection end is in contact with the one end part outside the medium carrying corresponding range of the annular body for detecting, via the first temperature detection end, the temperature of the annular body; and 
 a controller that detects, via the temperature sensor, the temperature of the annular body and in response to a result of the detection, switches a processing mode of a heat and pressure application process in which heat and pressure are applied to the medium while the medium is carried in a manner being sandwiched by the annular body and the pressure application part. 
 
     
     
       11. The fuser according to  claim 10 , wherein
 the controller, when the processing mode of the heat and pressure application process is switched, controls a carrying speed at which the medium is carried by the annular body and controls the fuser part heat generation body. 
 
     
     
       12. The fuser according to  claim 11 , wherein
 the controller, when it is detected via the temperature sensor that the temperature of the annular body has reached a predetermined temperature that is higher than a minimum temperature required for applying heat to the medium, controls to reduce the carrying speed of the medium to a speed slower than the carrying speed before the detection and controls the fuser part heat generation body to reduce a heat generation amount to an amount smaller than the heat generation amount before the detection. 
 
     
     
       13. The fuser according to  claim 1 , wherein
 the pressure application part is a pressure application annular body that is supported in a manner rotatable in a rotation direction opposite to a rotation direction of the annular body and in a manner that an outer surface of the pressure application annular body is pressed against an outer surface of the annular body. 
 
     
     
       14. A fuser comprising:
 a pressure application part that applies pressure to a medium for forming a print image; 
 an annular body that is rotatably supported for carrying the medium in a manner that the medium is sandwiched between the annular body and the pressure application part for applying heat to the medium for forming the print image; 
 a fuser part heat generation body that is arranged on an inner side of the annular body for generating heat to apply heat to the annular body; 
 a first temperature detection end that is arranged in contact with one end part outside a medium caring corresponding range of a surface of the annular body and detects temperature of the annular body outside the medium carrying corresponding range, the medium carrying corresponding range being a range in which the medium is carried; and 
 a heat generation interruption part that, in response to the temperature of the annular body that is detected via the first temperature detection end, interrupts heat generation of the fuser part heat generation body, wherein 
 the pressure application part is a pressure application annular body that is supported in a manner rotatable in a rotation direction opposite to a rotation direction of the annular body and in a manner that an outer surface of the pressure application annular body is pressed against an outer surface of the annular body, and 
 the fuser further comprises:
 a pressure application part heat generation body that is arranged on an inner side of the pressure application annular body and generates heat to apply heat to the pressure application annular body; and 
 a pressure application part heat generation interruption part that is arranged in a manner that a second temperature detection end is in contact with one end part outside a medium carrying corresponding range of the pressure application annular body and, in response to temperature of the pressure application annular body that is detected via the second temperature detection end, interrupts heat generation of the pressure application part heat generation body. 
 
 
     
     
       15. The fuser according to  claim 14 , wherein
 the pressure application part heat generation body is arranged directly to apply the heat to the medium carrying corresponding range and the one end part of the pressure application annular body. 
 
     
     
       16. The fuser according to  claim 14  wherein
 the pressure application part heat generation interruption part is arranged in a manner that the second temperature detection end is in contact with the one end part of an outer surface of the pressure application annular body. 
 
     
     
       17. The fuser according to  claim 16 , wherein
 the pressure application annular body comprises:
 a pressure application roller that is supported rotatable in the opposite rotation direction for applying pressure to the medium; 
 a pressure application contact member that is arranged at a predetermined distance from the pressure application roller; and 
 an annular pressure application belt that applies pressure to the medium by being pressed against the annular body via the pressure application roller in a state being hung on the pressure application roller, wherein 
 
 the pressure application roller and the pressure application contact part are arranged on an inner side of the pressure application belt, 
 the pressure application roller and the pressure application contact part respectively oppose the drive roller and the fuser contact member and sandwich the annular body therebetween, and here a sandwiching part is formed between a first sandwiching point (pt 1 ) where the drive roller and the pressure application roller press against each other and a second sandwiching point (pt 2 ) where the fuser contact member and the pressure application contact part press against each other, and 
 the pressure application part heat generation interruption part is arranged in a manner that the second temperature detection end is pressed against a portion opposing the sandwiching part on an outer surface of the pressure application belt. 
 
     
     
       18. The fuser according to  claim 16 , wherein
 the pressure application annular body comprises:
 a pressure application roller that is supported rotatable in the opposite rotation direction for applying pressure to the medium; 
 a pressure application contact member that is arranged at a predetermined distance from the pressure application roller; and 
 an annular pressure application belt that applies pressure to the medium by being pressed against the annular body via the pressure application roller in a state being hung on the pressure application roller, wherein 
 
 the pressure application roller and the pressure application contact part are arranged on an inner side of the pressure application belt, 
 the pressure application roller and the pressure application contact part respectively oppose the drive roller and the fuser contact member and sandwich the annular body therebetween, and here a sandwiching part is formed between a first sandwiching point (pt 1 ) where the drive roller and the pressure application roller press against each other and a second sandwiching point (pt 2 ) where the fuser contact member and the pressure application contact part press against each other, and 
 the pressure application part heat generation interruption part is arranged in a manner that the second temperature detection end is pressed against a second flexible portion (2utp) that is other than the sandwiching part on the outer surface of the pressure application belt. 
 
     
     
       19. The fuser according to  claim 16 , wherein
 the pressure application contact member is a pressure application driven roller that rotates in conjunction with the rotation of the drive roller, and 
 the second temperature detection end is positioned on the flexible portion, which is between a vertical tangential line at a most downstream position in a medium carrying direction on an outer periphery of the pressure application roller and a vertical tangential line at a most upstream position in the medium carrying direction on an outer periphery of the pressure application part driven roller. 
 
     
     
       20. The fuser according to  claim 18 , wherein
 the pressure application contact member is a pressure application part driven roller, the pressure application part driven roller rotates in response to the rotation of the drive roller, and 
 the second sandwiching point (pt 2 ) is formed between the pressure application part driven roller and the driven roller. 
 
     
     
       21. A fuser comprising:
 a pressure application part that applies pressure to a medium for forming a print image; 
 an annular body that is rotatably supported for carrying the medium in a manner that the medium is sandwiched between the annular body and the pressure application part for applying heat to the medium for forming the print image; 
 a fuser part heat generation body that is arranged on an inner side of the annular body for generating heat to apply heat to the annular body; 
 a first temperature detection end that is arranged in contact with one end part outside a medium carrying corresponding range of a surface of the annular body and detects temperature of the annular body outside the medium carrying corresponding range, the medium carrying corresponding range being a range in which the medium is carried; 
 a heat generation interruption part that, in response to the temperature of the annular body that is detected via the first temperature detection end, interrupts heat generation of the fuser part heat generation body; 
 a drive roller that drives the annular body to rotate; and 
 a fuser contact member that is arranged at a predetermined distance from the drive roller, wherein 
 the annular body is an annular belt, 
 the drive roller and the fuser contact member are arranged on an inner side of the belt, and further the belt rotates in accordance with rotation of the drive roller, 
 the drive roller and the fuser contact member both oppose the pressure application part and the belt is sandwiched therebetween, and thereby a predetermined pressure is applied to the belt and the carried medium, and here a sandwiching part is formed between a first sandwiching point (pt 1 ) where the drive roller and the pressure application part press against each other and a second sandwiching point (pt 2 ) where the fuser contact member and the pressure application part press against each other, and 
 the heat generation interruption part is arranged in a manner that the first temperature detection end is pressed against a first flexible portion (1utp) that is a portion other than the sandwiching part on an outer surface of the belt.